Interchangeable tools are used on agricultural ground working implements depending upon the type of ground to be worked and the reason for working the ground. In one arrangement these interchangeable tools have a socket on the tool and a tapered adaptor piece on the tine of the ground working implement and the tool is retained on the adaptor piece by the socket fitting onto the tapered adaptor piece. Such a tapered connection arrangement provides a positive grip for the tool onto the tine and is usually sufficient to hold the tool on but as it is a taper arrangement a slight movement of the tool off the adaptor piece can easily disengage the tool. Such an effect can occur when recoil of the tine occurs and hence it is necessary to have some method to prevent complete disengagement of the tool from the adaptor piece while still allowing for manufacturing tolerances of the adaptor piece and the socket of the tool.
Another object is to produce an arrangement for holding tools onto tines which is simpler than existing arrangements and has less parts or to at least provide the public with a useful alternative.
A further problem exists that as tools are formed from thicker material to give greater wear life the springiness of the tapered socket portion hence the ability to grip on to the adaptor piece is reduced. The present inventor has found ways by which the grip of the socket on to the adaptor piece can be improved.